Dispositivos de drenagem urbana de baixo impacto para diminuição da vazão no sistema de microdrenagem da bacia urbana do córrego Brejo Comprido, Palmas – TO

Abstract

The development proposed by the Low Impact Development (LID) involves profound transformations in drainage systems, understood here as the entire structure required for stormwater management, not just water catchment and transport devices. Thus, the objectives of this dissertation involve simulations in the microdrainage network, foreseeing the implantation of control devices at the source that make the system less impactful. The nature of the research is computational with majority use of SWMM. The watershed where the simulations were developed is the Brejo Comprido Stream. This microbasin has much of its extension in an urban area of the city of Palmas - TO, with drainage area covering almost the entire Central Master Plan of the city. Two simulation scenarios were considered, built taking into account the behavior of the watersheds as a function of design rain and return time. The first scenario is the current condition of the Brejo Comprido Stream microbasin, in which the runoff generated by rainwater is directed to the existing drainage network, without the presence of techniques that allow increased infiltration. In turn, the second scenario was configured on the concept of sustainable drainage system, idealized by the simulation of the implementation of LID techniques in the runoff management infrastructure. The LID devices predicted in the simulations were bioretention cells and infiltration trenches. The simulations were successful, with continuity errors related to runoff and flow propagation with values lower than 1.0%. The simulation of the trenches and bioretention cells implantation in the Brejo Comprido watershed resulted in reductions in the flow volumes of the micro drainage system, with a reduction of 48% in the network flow and 50% in the surface flow.